This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-302105 filed on Sep. 28, 2001.
The present invention relates to a vehicle alternator having impact and vibration resistant terminal connection.
In a vehicle alternator, an AC voltage induced at an armature coil is rectified to a DC voltage by a rectifier. The armature coil and rectifier are connected by soldering, welding, or utilizing a terminal connector attached to leads (lead-out wires) of the armature coil.
A vehicle alternator having a terminal connector crimped onto lead-out wires of armature coil is disclosed in U.S. Pat. No. 5,914,546 (JP-A-10-4646). Each lead-out wire has a round cross-section and the terminal connector is crimped onto a plurality of lead-out wires. Therefore, a contact area between each lead-out wire and terminal connector is insufficient. To augment electrical conductivity, solder or brazing filler metal is filled in the space around the lead-out wire.
In recent years, vehicle engines are reduced in weight and increased in power output. As a result, engines cause high vibration, resulting in severe condition of space in which the alternator is installed. Moreover, solder or brazing filler metal deteriorates over time. This may cause poor electrical connection between the lead-out wires and terminal.
The terminal connector requires space to provide the solder or brazing filler metal around the lead-out wires inside the crimping portion. Because of the space, the lead-out wire may not be placed in a proper position for crimping when it is inserted in the crimping portion. In such a case, the terminal connector is not properly crimped onto the lead-out wire and insufficient electrical connection may occur.
To counter the above problems, the lead-out wire may be deformed to a rectangular cross-section when crimping the terminal connector onto the wire. By deforming the lead-out wire to a rectangular cross-section, sufficient contact area is provided. However, this may cause broken wire because stress is applied to the deformed area when vibration occurs. Therefore, this alternative is not appropriate for practical application.
The present invention therefore has an objective to provide a vehicle alternator in which contact failure minimally occurs even under severe installation conditions.
A vehicle alternator of the present invention includes a stator, a rectifier, and terminal connectors. The stator has a stator core and an armature coil wound around the stator core. The armature coil has a rectangular cross-section. The rectifier converts an AC voltage induced at the armature coil to a DC voltage. The terminal connector has a crimping portion and a connecting portion. The crimping portion is used for crimping a lead (lead-out wire) of the armature coil. The connecting portion is connected to an input terminal of the rectifier with a screw.
When the terminal connector is crimped onto the lead-out wire, opposed surfaces of the lead-out wire have surface contact with the crimping portion of the terminal connector. As a result, sufficient contact area is provided with a minimal amount of plastic deformation of the lead-out wire. This reduces the occurrence of connection failures under the severe installation condition. This also reduces an amount of solder or brazing filler metal. The solder or brazing filler metal may not be needed if the crimping portion is well designed so that the lead-out wire has better surface contact with the terminal connector.